•A wall with variable thermophysical properties is proposed;•The wall thermal transmittance may be reduced up to ten times in a few minutes;•An yearly energy saving up to 50% can be reached with adaptive walls in buildings;•The most effective performance is found in moderate and hot climate zones. A new wall characterised by variable thermophysical properties is presented; this characteristic is obtained through the drowning of pipes on the inner and outer surfaces of the wall, hosting a heat-carrying fluid pushed by a pump, at the aim of transporting heat in the direction of the thickness of the wall, when desired. The concept of the environment-adaptive wall is described and numerical simulations are implemented to assess the performance of the system, which proved itself particularly quick to react to external solicitations. Beyond the stand-alone computational fluid dynamic analysis, the proposed solution is also tested in an entire construction by means of a dynamic simulation software, in different cities. Results showed that the better performance is obtained in moderate climate environments, especially in the hot season: a reduction even higher than the 50% of the heating and cooling envelope energy losses and gains can be reached, respect to a reference building realised with local state-of the-art criteria and subjected to the same operating conditions. The proposed system showed itself less incisive in cold climates.